The present invention generally relates to valves, and particularly to valves for interrupting the flow of a liquid under the pressure of a propulsion gas.
The invention is particularly useful in the context of pre-mix soft drinks dispensing installations, as will be now briefly described with reference to FIG. 1.
Hence, a typical dispensing installation comprises a series of dispensing spigots A1, A2, A3 for the different kinds of beverages--beer and carbonated drinks in the present example.
The supply of the beer and of the soft drink syrups to a refrigerator (and/or carbonated water mixing unit) B is achieved in the following manner.
A vessel C containing beer, and one or more vessels D containing syrup(s) are available and connected to the refrigerator as shown. The vessels are also connected to a supply source of pressurized CO.sub.2 --cylinder E. The CO.sub.2 gas is admitted into the vessels C and D, above the level of the liquid, which is thus forced to flow up, each through a siphon tube F extending within the vessel. The CO.sub.2 gas only serves as a propellant for the liquid contents of the vessel.
It will be now readily understood that once the level of the liquid lowers down to the (open) bottom of the siphon tube, gas will penetrate the installation and become supplied to the spigots A--rather than the desired liquid. This also signs the need to replace the exhausted vessel.
Upon replacement, an operation of gas evacuation from the system is required before ordinary, quality drink serving is resumed. This operation is annoying and time consuming.
It goes without saying that the stop valve herein proposed is useful for several other applications, for example in forced fuel supply systems where a similar problem is encountered.
It is thus the object of the invention to overcome the above described deficiency, namely to avoid the penetration of a propellant gas into a liquid supply system when the liquid is exhausted.
It is a further object of the invention to provide a valve which is readily installable into the existing beer or soft drinks syrup vessels standard connectors, namely without need to install a special, external or internal, device.